1. Field of the Invention
The present invention relates to a rolling bearing apparatus for rotatably supporting a wheel at a suspension of an automobile and having a rotation detecting apparatus for detecting a rotational speed and a rotational direction of the wheel, particularly relates to a rolling bearing apparatus having a pulser ring in the rotation detecting apparatus.
2. Description of the Related Art
There is a case in which a rolling bearing apparatus for supporting a wheel is installed with a rotation detecting apparatus used for controlling an antilock brake system (ABS) or the like in, for example, an automobile or the like. A rotation detecting apparatus is constituted to include a pulser ring and a sensor. The pulser ring is attached to a rotating ring of the rolling bearing apparatus and the sensor is attached to a fixed ring of the rolling bearing apparatus in a state of being opposed to the pulser ring. A state of rotating the pulser ring rotated in synchronism with the rotating ring is detected by the sensor to thereby detect a state of rotating a wheel. Generally, with regard to the above-described pulser ring, a magnetic property thereof is changed alternately in a circumferential direction and there are a magnetic piece type which is constituted by a metal ring in, for example, a combteeth shape as well as a metal ring provided with through holes at several portions of the circumference and a magnet type in which a support ring made of a metal is attached with a ring-like magnet constituted by arranging magnetic poles alternately in a circumferential direction.
The pulser ring is provided on a side of the rotating ring at one end portion in an axial direction of a ring-like space between the rotating ring and the fixed ring in a diameter direction interposed with a rolling is member of a ball or the like. In order to protect a portion of installing the pulser ring in the ring-like space such that dust and dirt or mud water or the like is prevented from invading the portion from outside, a sensor cover for partitioning the ring-like space from outside is provided. In the case of the prior art, the sensor cover is fitted to a side of the fixed ring opposed to the rotating ring provided with the pulser ring and the pulser ring is installed to seal by a seal member between the sensor cover and a metal ring or the like for fixing the pulser ring to the rotating ring (refer to, for example, Patent Reference 1).
[Patent Literature 1]: JP-A-2000-211311 (total pages, total drawings)
However, in the case of the above-described prior art, fitting of the sensor cover to the rotating ring is constituted by a structure of only fitting a cylindrical portion of the sensor cover to the rotating ring by press-fitting and therefore, it is not clear to what degree the sensor cover is fitted thereto in an axial direction. Therefore, there is a concern that the sensor cover is improperly pushed into an inner side thereof in the axial direction and particularly when the sensor cover and the pulser ring are arranged to be opposed to each other in the axial direction, there is a concern that the sensor cover is brought into contact with the pulser ring to damage the pulser ring. Further, even when the sensor cover is fitted thereto such that the sensor cover is not brought into contact with the pulser ring, in the case in which the rolling bearing apparatus are laminated to pile up for storage or transportation, there is a concern that the sensor cover is pushed thereinto by a bolt or the like and there is a concern that the pulser ring is damaged by the sensor cover which is pushed thereinto. Further, when a position of fitting the sensor cover is insufficient, an interval (clearance, air gap) in the axial direction between the pulser ring and the sensor is prolonged by being restricted by the position of the sensor cover and therefore, there is a concern that magnetic information of the pulser ring cannot accurately be detected by the sensor.
Particularly, when the clearance is intended to be as small as possible, the sensor cover and the pulser become further proximate to each other, or thin-walled formation of the sensor cover is achieved and therefore, the above-described problem in laminating to pile up the rolling bearing apparatus is liable to be posed.